During the International Hydrological Decade six representative basins were operated in Sweden. One of these represented an extensive raised bog area, Komosse, southwest of Lake Vättern. Another basin, Verka, north of Stockholm, represented a mixture of agricultural and forestry typical for this part of Sweden. A third covered an extensively glaciated area in the north of Sweden, well above the thimber line.

The typical forested areas in Sweden were represented by three basins, Velen between Lake Vänern and Lake Vättern; Kassjöån in the middle of Sweden and Lappträsket in the far north.

The research programs for all these basins included hydrochemistry mainly for the purpose of establishing balances of dissolved inorganic matter. The present paper discusses the results from the three forested basins, Velen, Kassjöån and Lappträsket.